Rocks & Minerals

Rock Cycle!

Igneous Rock:

- Igneous Rock is formed when magma cools.

Under The Ground:

- When Heated it becomes metamorphic rock.

- It can be melted again to form a new magma.

Above Ground:

- When weathered and eroded it becomes sedimentary rock!

Sedimentary Rock:

Formed when sediments compact into layers.

Inside The Earth:

- Can be heated under pressure to form metamorphic rock.

Above Ground:

- It can be weather AGAIN to form new sediment!

Metamorphic Rock:

Formed when rock changes under heat & pressure!

Inside The Earth:

- Can melt to form magma

Above Ground:

- Weather & Erode to Form Sediment

Minerals!

Ways To Identify Different Minerals:

COLOR

Most easily observed but the least useful!

Some minerals have a similar color, this is why it is least useful!

LUSTER

Luster is the way a mineral shines in reflected light.

There are several terms used to describe nonmetallic luster. Examples could be virtuous, like quartz or gypsum which is pearly.

STREAK

The streak of a mineral is the color of its powder when rubbed on a white tile.

Example a yellow rock has a green streak.

Streak color rarely varies!

CLEAVAGE

The cleavage of a mineral is its ability to split easily or separate along flat surfaces. Cleavage can even be observed on tiny mineral grains. This is a very useful property unlike color!

Example: Mica splits into thin sheets.

Minerals that don't split have things called fracture.

HARDNESS

The hardness of a mineral is its resistance to be scratched.

Example: Diamond is the hardest mineral and talc is softest.

Friedrich Mohs created a hardness scale. The minerals are sorted from a 1-10 scale.

CRYSTAL SHAPE

Crystal shape can be a useful property identifying minerals and if they had time and space to form crystals.

ACID TEST

Acid Test is testing if the mineral erodes when dropping certain liquid acids on it.

MALLEABLE

Test if the mineral can bend or mold into different shapes

MAGNETIC

See if the mineral is magnetic (Iron)

FLOURESCENT

Glows in the dark!

TASTE

Taste for minerals such as salt or Halite!

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